Szymura J M, Lunt D H, Hewitt G M
Population Biology Sector, School of Biological Sciences, University of East Anglia, Norwich.
Insect Mol Biol. 1996 May;5(2):127-39. doi: 10.1111/j.1365-2583.1996.tb00047.x.
The nucleotide sequence of the mitochondrial ND2, COI, COII, ATPase8, srRNA and nine tRNA genes have been sequenced from two individual of the meadow grasshopper Chorthippus parallelus. Comparisons are made to other insects for which the same regions are completely sequenced. Percentage A + T is found to be relatively low in C. parallelus though consistent with that of the other Orthopteran, Locusta migratoria. The relative number of substitutions observed in the different protein-coding genes was analysed between pairs of insect species sharing different levels of relatedness. A clear change in this rate was observed between the within-genus and between-genera comparisons. This change is interpreted in terms of the functional constraints acting on these four different genes. The patterns seem to result from an early saturation of COI and COII genes with synonymous substitutions, and a tolerance of ND2 and ATPase8 function to high levels of amino acid replacements. This analysis highlights a need for further sequence studies and comparisons between taxa of different levels of divergence in order to understand the patterns of mtDNA evolution on which many evolutionary investigations are based.
已对草原蝗虫（Chorthippus parallelus）的两个个体的线粒体ND2、COI、COII、ATPase8、srRNA和9个tRNA基因的核苷酸序列进行了测序。并与已完成相同区域全序列测定的其他昆虫进行了比较。发现草原蝗虫中A + T的百分比相对较低，不过与其他直翅目昆虫飞蝗（Locusta migratoria）一致。在具有不同亲缘关系水平的昆虫物种对之间，分析了不同蛋白质编码基因中观察到的替换相对数量。在属内比较和属间比较之间，观察到了这一比率的明显变化。这种变化是根据作用于这四个不同基因的功能限制来解释的。这些模式似乎是由于COI和COII基因同义替换的早期饱和，以及ND2和ATPase8功能对高水平氨基酸替换的耐受性所致。该分析强调需要进一步进行序列研究，并在不同分化水平的分类群之间进行比较，以便理解许多进化研究所基于的线粒体DNA进化模式。
